Donohoe: Age, growth, distribution, and food habits of Atractoscion nobilis 
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Mar Apr May Jun Jul Aug Sep 
Week 
Figure 10 
Seasonal pattern of spawning by white seabass in 1987 and 1988 as 
calculated from date of capture, age of settled fish, and an estimated 
two-day incubation period (Orhun, 1989). The ages of 50 fish were 
estimated directly from otoliths, the others from the age-length rela- 
tion shown in Figure 8. 
predators of small benthic fishes are present 
both within the white seabass nursery and 
in deeper water (Love et al., 1986). Some of 
these predators, such as the California 
lizardfish ( Synodus lucioceps), are less 
abundant within the white seabass nurs- 
ery than at 12-18 m, whereas other spe- 
cies, such as California halibut ( Para - 
lichthys calif ornicus), are more abundant 
within the nursery than in deeper water 
(Ford, 1965; Love et al., 1986; Allen, 1990). 
However predation risk will depend not only 
on the total number of vertebrate and in- 
vertebrate predators at a particular depth, 
but also on the size and ontogenetic distri- 
bution of predators as well as species-spe- 
cific probabilities of encounter, detection, 
and capture (Bailey and Houde, 1989; 
Fuiman and Margurran, 1994). A detailed 
study is required to determine if the risk of 
predation to settled white seabass is lower 
in the nursery than in deeper waters. 
Conclusion 
The shallow water along the open coast just 
beyond the breaking waves appears to be 
the primary nursery for white seabass. Sur- 
vival of young white seabass is probably 
influenced by the abundance of mysids and 
drifting macrophytes as well as by water 
temperature in the nursery during spring 
and summer. However, it is not known if survival in 
the nursery is an important determinant of year-class 
success for white seabass. Year-class success in most 
marine fishes is generally believed to be set during 
the larval stage. However, poor correlations between 
larval abundance and subsequent recruitment for 
some species indicate that survival of older fish, per- 
haps early juveniles, may be equally important 
(Sissenwine, 1984; Bradford, 1992). Further studies 
are needed to evaluate the importance of survival of 
early life history stages in determining the distribu- 
tion and abundance of white seabass populations off 
southern California. 
Acknowledgments 
I am deeply indebted to Sharon Kramer for provid- 
ing specimens and data from her survey of the shal- 
low water flatfishes of San Diego County. I also thank 
John Butler who provided laboratory space and 
equipment; P. Dutton, D. Griffith, M. Maloney, and 
M. Shane who assisted with field collections; S. 
Johnson, D. Mayer, R. Orhun and others who reared 
white seabass; K. Miller-McClune who assisted with 
data analysis; John Hunter, Richard Ford, and Stuart 
Hurlbert who reviewed and greatly improved an early 
version of the manuscript; and three anonymous re- 
viewers for helpful comments on the final manu- 
script. This study was supported by the Ocean Re- 
source Enhancement and Hatchery Program 
(OREHP) through grants to Richard Ford of San Di- 
ego State University and Donald B. Kent of Sea World 
Research Institute. OREHP is administered by the 
California Department of Fish and Game. This study 
was conducted in partial fulfillment of the requirements 
of a Masters degree at San Diego State University. 
Literature cited 
Allen, L. G., and M. P. Franklin. 
1988. Distribution and abundance of young-of-the-year 
white seabass, Atractoscion nobilis, in the vicinity of Long 
